U.S. patent number 9,539,029 [Application Number 14/958,961] was granted by the patent office on 2017-01-10 for external fixator assembly.
This patent grant is currently assigned to GLOBUS MEDICAL, INC.. The grantee listed for this patent is GLOBUS MEDICAL, INC.. Invention is credited to Barclay Davis, Sergio Muniz.
United States Patent |
9,539,029 |
Muniz , et al. |
January 10, 2017 |
External fixator assembly
Abstract
External fixator assemblies, systems, and methods thereof. An
external fixator system may include a plurality of fixator
assemblies configured to connect a plurality of pins, for example,
positioned on opposite sides of a fractured bone, with one more
rods. The fixator assemblies may include a plurality of clamp
assemblies which are configured to rotate relative to one another
when the fixator assembly is in an unlocked position.
Inventors: |
Muniz; Sergio (Philadelphia,
PA), Davis; Barclay (Glenmoore, PA) |
Applicant: |
Name |
City |
State |
Country |
Type |
GLOBUS MEDICAL, INC. |
Audubon |
PA |
US |
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Assignee: |
GLOBUS MEDICAL, INC. (Audubon,
PA)
|
Family
ID: |
57705910 |
Appl.
No.: |
14/958,961 |
Filed: |
December 4, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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14957793 |
Dec 3, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B
17/6416 (20130101); A61B 17/6425 (20130101); A61B
17/6466 (20130101); A61B 17/6475 (20130101); A61B
17/6483 (20130101) |
Current International
Class: |
A61B
17/00 (20060101); A61B 17/64 (20060101) |
Field of
Search: |
;606/54-59,324,277
;403/72,384,385,289 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Philogene; Pedro
Claims
What is claimed is:
1. An external fixator assembly comprising: a first shaft having a
first coupling end and a first free end; a second shaft having a
second coupling end and a second free end; a coupling pivotally
retaining the first coupling end and the second coupling end; a
first clamp assembly disposed on the first shaft between the
coupling and the first free end, the first clamp assembly
comprising: a first inner clamp member disposed proximate to the
coupling, the first inner clamp member having a first inner slot; a
first outer clamp member disposed proximate to the first free end,
the first outer clamp member having a first outer slot; and a first
biasing member disposed in the first inner slot and the first outer
slot such that first biasing member biases the first inner clamp
member toward the first outer clamp member; and a second clamp
assembly disposed on the second shaft between the coupling and the
second free end, the second clamp assembly comprising: a second
inner clamp member disposed proximate to the coupling, the second
in the clamp member having a second inner slot; a second outer
clamp disposed proximate to the second free end, the second outer
clamp member having a second outer slot; and a second biasing
member disposed in the second inner slot and the second outer slot
such that the second biasing member biases the second inner clamp
member toward the second outer clamp member.
2. The external fixator assembly according to claim 1, wherein the
coupling comprises: a first cup having a first opening extending
axially therethrough, the first opening having a first opening
diameter; and a second cup having a second opening extending
axially therethrough, the second opening having a second opening
diameter.
3. The external fixator assembly according to claim 2, wherein the
first shaft has a first outer diameter at the first coupling end,
the first outer diameter being smaller than the first opening
diameter.
4. The external fixator assembly according to claim 3, wherein the
second shaft has a second outer diameter at the second coupling
end, the second outer diameter being smaller than the second
opening diameter.
5. The external fixator assembly according to claim 1, wherein the
first shaft extends through the first inner slot and the first
outer slot.
6. The external fixator assembly according to claim 5, wherein the
first shaft retains the first biasing member in the first inner
slot and the first outer slot.
7. The external fixator assembly according to claim 6, wherein the
second shaft extends through the second inner slot and the second
outer slot.
8. The external fixator assembly according to claim 7, wherein the
second shaft retains the second biasing member in the second inner
slot and the second outer slot.
9. An external fixator system comprising: an external fixator
assembly comprising: a first shaft having a first coupling end and
a first free end; a second shaft having a second coupling end and a
second free end; a coupling pivotally retaining the first coupling
end and the second coupling end; a first clamp assembly disposed on
the first shaft between the coupling and the first free end, the
first clamp assembly comprising: a first inner clamp member
disposed proximate to the coupling, the first inner clamp member
having a first inner slot; a first outer clamp member disposed
proximate to the first free end, the first outer clamp member
having a first outer slot; and a first biasing member disposed in
the first inner slot and the first outer slot such that first
biasing member biases the first inner clamp member toward the first
outer clamp member; and a second clamp assembly disposed on the
second shaft between the coupling and the second free end, the
second clamp assembly comprising: a second inner clamp member
disposed proximate to the coupling, the second in the clamp member
having a second inner slot; a second outer clamp disposed proximate
to the second free end, the second outer clamp member having a
second outer slot; and a second biasing member disposed in the
second inner slot and the second outer slot such that the second
biasing member biases the second inner clamp member toward the
second outer clamp member; a pin configured to engage bone, a
portion of the pin being received in the first or second clamp
assembly; and a rod received in the other of the first or second
clamp assembly.
10. The external fixator system according to claim 9, wherein the
pin is positioned between the first inner and outer clamp member or
the second inner and outer clamp member and the rod is positioned
between the other of the first inner and outer clamp member or the
second inner and outer clamp member.
11. The external fixator system according to claim 9, wherein the
first or second clamp assembly is rotatable relative to the other
of the first or second clamp assembly when unlocked.
12. The external fixator system according to claim 9, wherein the
first or second clamp assembly is fixed in position relative to the
other of the first or second clamp assembly when locked.
13. The external fixator system according to claim 9 further
comprising a second pin configured to engage bone, and a second
external fixator assembly having first and second clamp assemblies,
wherein the second pin is received in the first or second clamp
assembly of the second external fixator and the rod is received in
the other of the first or second clamp assembly of the second
external fixator, thereby externally stabilizing the bone.
14. The external fixator system according to claim 9, wherein the
coupling comprises: a first cup having a first opening extending
axially therethrough, the first opening having a first opening
diameter; and a second cup having a second opening extending
axially therethrough, the second opening having a second opening
diameter.
15. The external fixator system according to claim 14, wherein the
first shaft has a first outer diameter at the first coupling end,
the first outer diameter being smaller than the first opening
diameter.
16. The external fixator system according to claim 15, wherein the
second shaft has a second outer diameter at the second coupling
end, the second outer diameter being smaller than the second
opening diameter.
17. The external fixator system according to claim 9, wherein the
first shaft extends through the first inner slot and the first
outer slot.
18. The external fixator system according to claim 17, wherein the
first shaft retains the first biasing member in the first inner
slot and the first outer slot.
19. The external fixator system according to claim 18, wherein the
second shaft extends through the second inner slot and the second
outer slot.
20. The external fixator system according to claim 19, wherein the
second shaft retains the second biasing member in the second inner
slot and the second outer slot.
Description
BACKGROUND
Field of the Invention
The present invention relates to external fixator assemblies, and,
in particular, to external fixator assemblies having a plurality of
clamps.
Description of the Related Art
External fixators have long been used in trauma incidents as a
long-term care solution for reducing fractures and promoting bone
healing. Recently, however, external fixators have been used for
poly-traumatic patients as a way to stabilize fractures until a
more definitive method of fixation can be determined and applied.
The use of current external fixators to perform this temporary
stabilization can be bulky and time-consuming.
Accordingly, there exists a need for lightweight, quick-assembly
external fixators.
SUMMARY
This Summary is provided to introduce a selection of concepts in a
simplified form that are further described below in the Detailed
Description. This Summary is not intended to identify key features
or essential features of the claimed subject matter, nor is it
intended to be used to limit the scope of the claimed subject
matter.
According to one embodiment, an external fixator system may include
a plurality of external fixator assemblies configured to connect a
plurality of pins, for example, positioned on opposite sides of a
fractured bone, with one more rods. The fixator assemblies may
include a plurality of clamp assemblies which are configured to
rotate relative to one another when the fixator assembly is in an
unlocked position. Once the relative positioning of the pins and/or
rods is achieved, for example, to stabilize the bone or bones, the
fixator assemblies may be moved to a locked position, such that the
clamp assemblies are fixed in position and no longer able to rotate
relative to one another.
In one embodiment, the external fixator assembly includes a shaft
having a distal end and a proximal end. The proximal end has at
least one external thread. A plurality of clamp assemblies extends
along the shaft from the distal end to the proximal end. A biasing
member is disposed between adjacent of the plurality of clamp
assemblies. A cap assembly is disposed over the proximal end of the
shaft. The cap assembly is adapted to bias the plurality of clamp
assemblies toward the distal end of the shaft.
In an alternative embodiment, the external fixator assembly
includes a shaft comprising a distal end having a flange and a
proximal end having at least one external thread. A clamp assembly
is disposed along the shaft, proximal of the distal flange. A
ratchet assembly biases the clamp assembly toward the distal
flange. The ratchet assembly comprises a ratcheting buttress having
a radially extending buttress flange and a hole extending through
the flange. The hole is sized to allow the shaft to extend
therethrough. A plurality of fingers extends proximally around the
hole. Each of the plurality fingers has a plurality of internal
ratchet teeth adapted to engage the least one external thread on
the proximal end on the shaft. A ratchet housing has a distal end
having a radially extending housing flange adapted to engage the
buttress flange and a proximal end having at least one internal
thread adapted to threadably engage the at least one external
thread on the shaft.
In still another alternative embodiment, the external fixator
assembly includes a ratchet assembly. The ratchet assembly
comprises a ratcheting buttress and a ratchet housing. The
ratcheting flange having an annular flange having a buttress axial
hole formed therein, a tang extending outwardly from the annular
flange in a first direction, and a plurality of fingers extending
outwardly from the annular flange in the first direction. The
plurality of fingers surrounds the hole. Each of the plurality
fingers includes a plurality of internal ratchet teeth. The ratchet
housing has an annular flange having a housing axial hole formed
therein and a body attached to the flange. The annular flange has
an external contoured surface, a first radially extending cavity
adapted to receive the annular flange of the wrenching buttress,
and an axially extending slot adapted to receive the tang. The body
has a plurality of external flat surfaces extending around an outer
perimeter thereof, a second radially extending cavity adapted to
receive the plurality of fingers, and an internally threaded
passage adjacent to the second radially extending cavity.
In yet another alternative embodiment, the external fixator
assembly comprises a first shaft having a first coupling end and a
first free end, a second shaft having a second coupling end and a
second free end, and a coupling pivotally retaining the first
coupling end and the second coupling end. A first clamp assembly is
disposed on the first shaft between the coupling and the first free
end. The first clamp assembly comprises a first inner clamp member
disposed proximate to the coupling. The first inner clamp member
has a first inner slot. A first outer clamp member is disposed
proximate to the first free end. The first outer clamp member has a
first outer slot. A first biasing member is disposed in the first
inner slot and the first outer slot such that first biasing member
biases the first inner clamp member toward the first outer clamp
member. A second clamp assembly is disposed on the second shaft
between the coupling and the second free end. The second clamp
assembly comprises a second inner clamp member disposed proximate
to the coupling. The second in the clamp member has a second inner
slot. A second outer clamp is disposed proximate to the second free
end. The second outer clamp member has a second outer slot. A
second biasing member is disposed in the second inner slot and the
second outer slot such that the second biasing member biases the
second inner clamp member toward the second outer clamp member.
BRIEF DESCRIPTION OF THE DRAWINGS
Other aspects, features, and advantages of the present invention
will become more fully apparent from the following detailed
description, the appended claims, and the accompanying drawings in
which like reference numerals identify similar or identical
elements.
FIG. 1 is a perspective view of an external fixator assembly
according to a first exemplary embodiment being used to fixate
adjacent bones;
FIG. 1A is a perspective view of the external fixator assembly
shown in FIG. 1 being used to fixate broken pieces of the same
bone;
FIG. 2 is a perspective view of the external fixator assembly shown
in FIG. 1 with a rod and a pin connected thereto;
FIG. 3 is an exploded perspective view of the external fixator
assembly shown in FIG. 1;
FIG. 4 is a side elevational view, in section, of the external
fixator assembly shown in FIG. 1;
FIG. 5 is an exploded sectional view of a ratchet assembly used
with the external fixator assembly shown in FIG. 1;
FIG. 6 is a perspective view of external fixator assembly according
to a second exemplary embodiment being used to fixate adjacent
bones;
FIG. 7 is a perspective view of the external fixator assembly shown
in FIG. 6 with rods connected thereto;
FIG. 7A is a perspective view of the external fixator assembly
shown in FIG. 6 with a rod and a pin connected thereto;
FIG. 8 is an exploded perspective view of the external fixator
assembly shown in FIG. 6;
FIG. 9 is a side elevational view, in section, of the external
fixator assembly shown in FIG. 6; and
FIG. 10 is a side elevational view, in section, of the external
fixator assembly shown in FIG. 9, with one shaft pivoted relative
to the other shaft.
DETAILED DESCRIPTION
In the drawings, like numerals indicate like elements throughout.
Certain terminology is used herein for convenience only and is not
to be taken as a limitation on the present invention. The
terminology includes the words specifically mentioned, derivatives
thereof and words of similar import. The embodiments illustrated
below are not intended to be exhaustive or to limit the invention
to the precise form disclosed. These embodiments are chosen and
described to best explain the principle of the invention and its
application and practical use and to enable others skilled in the
art to best utilize the invention.
Reference herein to "one embodiment" or "an embodiment" means that
a particular feature, structure, or characteristic described in
connection with the embodiment can be included in at least one
embodiment of the invention. The appearances of the phrase "in one
embodiment" in various places in the specification are not
necessarily all referring to the same embodiment, nor are separate
or alternative embodiments necessarily mutually exclusive of other
embodiments. The same applies to the term "implementation."
As used in this application, the word "exemplary" is used herein to
mean serving as an example, instance, or illustration. Any aspect
or design described herein as "exemplary" is not necessarily to be
construed as preferred or advantageous over other aspects or
designs. Rather, use of the word exemplary is intended to present
concepts in a concrete fashion.
Additionally, the term "or" is intended to mean an inclusive "or"
rather than an exclusive "or". That is, unless specified otherwise,
or clear from context, "X employs A or B" is intended to mean any
of the natural inclusive permutations. That is, if X employs A; X
employs B; or X employs both A and B, then "X employs A or B" is
satisfied under any of the foregoing instances. In addition, the
articles "a" and "an" as used in this application and the appended
claims should generally be construed to mean "one or more" unless
specified otherwise or clear from context to be directed to a
singular form.
Unless explicitly stated otherwise, each numerical value and range
should be interpreted as being approximate as if the word "about"
or "approximately" preceded the value of the value or range.
The use of figure numbers and/or figure reference labels in the
claims is intended to identify one or more possible embodiments of
the claimed subject matter in order to facilitate the
interpretation of the claims. Such use is not to be construed as
necessarily limiting the scope of those claims to the embodiments
shown in the corresponding figures.
It should be understood that the steps of the exemplary methods set
forth herein are not necessarily required to be performed in the
order described, and the order of the steps of such methods should
be understood to be merely exemplary. Likewise, additional steps
may be included in such methods, and certain steps may be omitted
or combined, in methods consistent with various embodiments of the
present invention.
Although the elements in the following method claims, if any, are
recited in a particular sequence with corresponding labeling,
unless the claim recitations otherwise imply a particular sequence
for implementing some or all of those elements, those elements are
not necessarily intended to be limited to being implemented in that
particular sequence.
Also for purposes of this description, the terms "couple,"
"coupling," "coupled," "connect," "connecting," or "connected"
refer to any manner known in the art or later developed of joining
or connecting two or more elements directly or indirectly to one
another, and the interposition of one or more additional elements
is contemplated, although not required. Conversely, the terms
"directly coupled," "directly connected," etc., imply the absence
of such additional elements.
The present disclosure provides embodiments of external fixators
that can be used to secure bone fractures. The inventive external
fixators provide connections that enable a surgeon to rapidly and
securely stabilize the fracture.
According to one embodiment, an external fixator system may include
a plurality of external fixator assemblies configured to connect a
plurality of pins, for example, positioned on opposite sides of a
fractured bone, with one more rods. Each fixator assembly may
include a plurality of clamp assemblies which are configured to
rotate relative to one another when the fixator assembly is in an
unlocked position. Once the relative positioning of the pins and/or
rods is achieved, for example, to stabilize the fractured bone or
bones, the fixator assemblies may be moved to a locked position,
such that the clamp assemblies are fixed in position, thereby
stabilizing the fracture.
Referring to FIGS. 1-5, an external fixator assembly 100 ("fixator
assembly 100") according to a first exemplary embodiment is shown.
As shown specifically in FIGS. 1 and 1A, fixator assembly 100 is
used in conjunction with rods 50 and pins 60 to secure and
stabilize adjacent bones 70, 72 (shown in FIG. 1) or to stabilize
broken pieces 74, 76 of the same bone 70 (shown in FIG. 1A). While
a femur 70 and a tibia 72 are shown in FIG. 1, and femur 70 is
shown in FIG. 1A, those skilled in the art will recognize that
fixator assembly 100, along with rods 50 and pins 60, can be used
to fixate other bones, and other bone pairs as well. Examples of
bones may include, but are not limited to, the femur, tibia,
fibula, humerus, radius, ulna, and phalanges. Although specific
configurations of the external fixator systems are exemplified
herein, it will be appreciated that the number, type, and location
of rods 50, pins 60, and fixator assemblies 100 can be modified or
changed based on the type and location of the bone, fracture,
surgeon preference, and the like.
As shown in FIG. 2, fixator assembly 100 can be used to releasably
secure rod 50 and pin 60 through the use of a plurality of
connector assemblies. In an exemplary embodiment, rod 50 can be
constructed from a rigid material, such as, for example, a carbon
fiber, and can optionally be coated with a material, such as, for
example, titanium, to make rod 50 more compatible with MRI use. It
is contemplated that the rod 50 may be formed of any suitable
material having suitable properties for this application. Rod 50
has a first diameter. The length of rod 50 can be varied depending
on the need for a particular application.
Pin 60 can include a bone-engaging end, such as a self-tapping end
62, that is inserted into bone 70, 72. The pin 60 may also be
constructed from any suitable biocompatible material. Optionally,
end 62 can be coated with an antimicrobial material, such as, for
example, silver or silver ions, in order to reduce the likelihood
of infection. Pin 60 has a second diameter, smaller than the first
diameter of rod 50. The length and diameter of pin 60 can vary,
depending on the patient or the injury, as well as surgeon
preference.
While FIGS. 1A and 2 show fixator assembly 100 being used to secure
a single rod 50 and a single pin 60, those skilled in the art will
recognize that fixator assembly 100 can, depending upon the
particular situation and injury, be used to connect two rods 50, as
shown in FIG. 1, or even two pins 60 (not shown).
As shown in FIG. 4, fixator assembly 100 includes a longitudinal
axis 102 extending therethrough. As used herein, the terms
"longitudinal", "longitudinally", "axial", and "axially" refer to
directions along the length of longitudinal axis 102 or to
directions extending parallel to longitudinal axis 102. Further,
the terms "radial" and "radially" refer to directions extending
perpendicular to or extending outwardly from longitudinal axis
102.
Referring now to FIGS. 2 and 3, fixator assembly 100 includes a
shaft 110 and a plurality of clamp assemblies 120, 150 extending
along shaft 110. Shaft 110 extends along longitudinal axis 102. A
biasing member 160 is disposed between adjacent of the plurality of
clamp assemblies 120, 150. A cap, or ratchet, assembly 170 secures
clamp assemblies 120, 150 onto shaft 110.
Shaft 110 has a distal end 112 and a proximal end 114 extending
away from distal and 112. As used herein with respect to fixator
assembly 100, the term "distal" refers to a direction toward the
bottom of the page of FIG. 4, and the term "proximal" refers to a
direction toward the top of the page of FIG. 4.
Distal end 112 includes a radially extending flange 116 and at
least one flat surface 117 extending proximally of flange 116.
While FIG. 4 shows two flat surfaces 117, those skilled in the art
will recognize that shaft 110 can include more or less than two
flat surfaces 117.
Proximal end 114 of shaft 110 has at least one external thread 118.
Optionally, a length of shaft 115 between distal end 112 and
proximal end 114 can be generally circular, that is, devoid of any
flat surfaces or threads. Shaft 110 is sufficiently long to allow
for the insertion of clamp assemblies 120, 150 and ratchet assembly
170 thereon.
Clamp assemblies 120, 150 extend along shaft 110 from distal end
112 toward proximal end 114 such that clamp assembly 120 engages
flange 116 and clamp assembly 150 engages clamp assembly 120. While
two clamp assemblies 120, 150 are shown, those skilled in the art
will recognize that more than two clamp assemblies 120, 150 can be
used with fixator assembly 100. Alternatively, it can be envisioned
that only a single clamp assembly 120 is used with fixator assembly
100.
Clamp assemblies 120, 150 may be, although not necessarily,
identical to each other. Clamp assembly 120 includes a lower member
122 and an upper member 124 extending proximally of lower member
122. Lower member 122 includes an axially extending passage 126
that is sized to allow shaft 110 to extend therethrough. Passage
126 can include internal flat surfaces 128 that are adapted to
engage with flat surfaces 117 on shaft 110 to prevent lower member
122 of clamp assembly 120 from rotating with respect to shaft
110.
Lower member 122 includes a first generally U-shaped portion 130
having a radius that is sized to receive a portion of rod 50. Lower
member 122 also includes a second generally U-shaped portion 131,
radially disposed away from first concave portion 130, having a
radius that is sized to receive a portion of pin 60. As shown in
FIG. 3, lower member 122 also includes a plurality of tangs 132
extending outwardly therefrom in a proximal direction toward upper
member 124.
Upper member 124 includes an axially extending passage 134 that is
sized to allow shaft 110 to extend therethrough. Upper member 136
further includes a first generally inverted U-shaped portion 136
having a radius that is sized to receive a portion of rod 50, such
that, when upper member 124 is biased toward lower member 122, rod
50 is received in a cavity 138 formed by first generally U-shaped
portion 130 of lower member 122 and first generally inverted
U-shaped portion 136 of upper member 124.
Upper member 124 also includes a second generally inverted U-shaped
portion 140, radially disposed away from first generally inverted
U-shaped portion 136, having a radius that is sized to receive a
portion of pin 60, such that, when upper member 124 is biased
toward lower member 122, pin 60 is received in a cavity 142 formed
by second generally inverted U-shaped portion 131 of lower member
122 and second generally inverted U-shaped 140 of upper member
124.
As shown in FIG. 3, upper member 124 also includes a plurality of
slots 144 formed therein, such that each slot 144 is adapted to
releasably receive a tang 132 from lower member 122, thereby
preventing upper member 124 from rotating about longitudinal axis
102 relative to lower member 122. Upper member 124 also includes a
spring cavity 146 that is sized to receive biasing member 160. A
toothed locking half 148 surrounds spring cavity 146.
Clamp assembly 150 is similar to clamp assembly 120 with the
exception that, instead of internal flat surfaces 128, clamp
assembly 150 includes a member 122' having an axially extending
passage 126' sufficiently larger than the diameter of shaft 110
such that clamp assembly 150 is freely rotatable about shaft 110
and is also rotatable relative to clamp assembly 120. As shown in
FIGS. 3 and 4, clamp assembly 150 is inserted over shaft 110
"upside down" relative to clamp 120 such that toothed locking half
148 of clamp assembly 150 is engageable with toothed locking half
148 of clamp assembly 120 such that, when clamp assembly 150 is
biased against clamp assembly 120, toothed locking half 148 of
clamp assembly 150 engages toothed locking half 148 of clamp
assembly 120, preventing rotation of clamp assembly 150 with
respect to clamp assembly 120.
Each toothed locking half 148 includes a plurality of teeth or the
like. In an exemplary embodiment, each toothed locking half 148
includes about 90 teeth, such that clamp assembly 150 can be
indexed with respect to clamp assembly 120 about 4.degree.. Those
skilled in the art, however, will recognize that each toothed
locking half 148 can include more or less than 90 teeth, such that
the amount indexing of clamp assembly 150 with respect clamp
assembly 120 is adjustable accordingly.
As shown in FIG. 3, biasing member 160 is disposed between clamp
assembly 120 and clamp assembly 150 and is retained between clamp
assembly 120 and clamp assembly 150 within spring cavities 146. In
an exemplary embodiment, biasing member 160 is a helical spring,
although those skilled in the art will recognize that other types
of biasing members can be used. Biasing member 160 biases clamp
assembly 120 and clamp assembly 150 apart from each other, such
that clamp assembly 120 and clamp assembly 150 securely engage rod
50 that may be inserted into cavity 138 and/or pin 160 that may be
inserted into cavity 142.
Referring to FIGS. 3-5, ratchet assembly 170 is disposed over
proximal end 114 of shaft 110, such that ratchet assembly 170
biases clamp assemblies 120, 150 toward distal end 112 of shaft 110
and flange 116 so that clamp assemblies 120, 150 are not rotatable
with respect to each other. A washer 162 is axially disposed
between second clamp assembly 150 and ratchet assembly 170 to
distribute compressive forces applied by ratchet assembly 170 onto
clamp assembly 150.
Ratchet assembly 170 comprises includes a ratcheting buttress 172
that is adapted to translate axially along shaft 110 from proximal
end 114 toward distal end 112. Ratcheting buttress 172 comprises a
radially extending annular flange 174 having an axially extending
hole 176 therein. Hole 176 is sized to allow shaft 112 to extend
therethrough. A tang 177 extends longitudinally outwardly from
flange 174.
A plurality of fingers 178 extend proximally around hole 176. Each
of the plurality of fingers 178 has a plurality of longitudinally
spaced internal ratchet teeth 180 adapted to engage external thread
118 on proximal end 114 of shaft 110. A gap 181 extends between
each of adjacent fingers 178 to allow fingers 178 to bias away from
longitudinal axis 102, thereby allowing thread 118 to ratchet along
ratchet teeth 180 when ratchet assembly 170 is pressed onto shaft
110.
A ratchet housing 182 is disposed over ratcheting buttress 172.
Ratchet housing 182 includes a distal end 184 having a radially
extending housing flange 186 that is adapted to engage buttress
flange 174. Flange 186 includes a slot 188 that is adapted to
receive tang 177 from flange 174 such that, when tang 177 is
inserted into slot 188, ratchet housing 182 is not rotatable
relative to ratcheting buttress 172.
An exterior surface of housing flange 186 includes a contoured
surface, such as, for example, a knurled surface, that provides a
gripping surface for the user to be able to manually rotate ratchet
housing 182 about shaft 110. An interior of housing flange 186
includes a first radially extending cavity 190 adapted to receive
annular flange 174 of ratchet buttress 172.
Ratchet housing 182 further includes a proximal body 192 having an
internally threaded passage 193 with at least one internal thread
194 adapted to threadably engage external thread 118 on shaft 110.
Body 192 further comprises a plurality of flat surfaces 196
extending around a perimeter thereof. Flat surfaces 196 allow for
the application of a tool, such as, for example, a wrench or other
torquing device (not shown) to tighten fixator assembly 100 in
order to secure rod(s) 50 and/or pin(s) 60. Body 192 also includes
a second radially extending cavity 198 that is adapted to receive
the plurality of fingers 178. As shown in FIG. 4, cavity 198 is
sufficiently large to allow fingers 178 to bias away from shaft 110
to allow ratcheting buttress 172 to be slid distally along shaft
110.
To assemble fixator assembly 100, first clamp assembly 120 is slid
from proximal end 114 of shaft 110 to distal end 112 shaft 110,
bottoming out on flange 116. First clamp assembly 120 is aligned
such that toothed locking half 148 is facing proximal end 114 of
shaft 100. Next, biasing member 160 is slid along shaft 110 such
that at least a portion of biasing member 160 is seated within
spring cavity 146.
Second clamp assembly 150 is then slid from proximal end 114 of
shaft 110, toward first clamp assembly 120. Second clamp assembly
150 is aligned such that toothed locking half 148 is facing distal
end 112 of shaft 100 so that at least a remaining portion of
biasing member 160 is seated within spring cavity 146 in second
clamp assembly 150 and so that toothed locking half 148 of second
clamp assembly 150 is facing toothed locking half 148 of first
clamp assembly 120.
Washer 162 is slid over shaft 110. Ratchet assembly 170 is then
slid over shaft 110 so that internal thread 194 engages external
threads 118 on shaft 110. At this point, cavities 138, 142 are
sufficiently large to allow rod 50 be slid into cavity 138 and pin
60 to be slid into cavity 142 and also to allow second clamp
assembly 150 to axially rotate relative to first clamp assembly
120.
In this condition, the surgeon can align rod 50 and pin 60 in
desired positions with respect to fixator assembly 100. The surgeon
can then provisionally tighten ratchet assembly 170 by further
sliding ratchet assembly 170 distally along shaft 110 and then
perform a final tightening of fixator assembly 100 by applying a
wrench or other court applying device (not shown) to flat surfaces
196 on ratchet housing 182 and rotating ratchet housing 182
relative to shaft 110.
Ratchet assembly 170 allows for the rapid application of clamp
assemblies 120, 150 onto bar 50 and/or pin 60. Ratchet assembly 170
also provides a quick method for provisional tightening of fixator
assembly 100 while the surgeon is assembling fixator assembly 100
with bar(s) 50 and pin(s) 60. Once set, a final tightening of
ratchet assembly 170 can be applied using a torque limiting
adapter, for example, under power.
According to one embodiment, a method of installing the external
fixator system, for example, at the site of one or more broken
bones, may include inserting one or more pins 60 into the afflicted
bone (for example, on opposite sides of the fracture); attaching
one or more fixator assemblies 100 to each pin 60; and securing the
one or more pins 60 to adjacent pins 60 by connecting one or more
rods 50 between adjacent fixator assemblies 100. If the construct
needs to be extended, for example, to bridge multiple bones or
multiple fractures, the same fixator assembly 100 can also be used
to connect two or more rods 50 together.
An alternative embodiment of an external fixator assembly 200
("fixator assembly 200") is shown in FIGS. 6-10. FIG. 6 shows
fixator assembly 200 being used with both rods 50 and pins 60 to
secure and stabilize adjacent bones 70, 72 in a patient. FIG. 7
shows fixator assembly 200 being used to secure two rods 50 in a
generally parallel arrangement, while FIG. 7A shows fixator
assembly 200 being used to secure a single rod 50 and a single pin
60 in a skewed arrangement.
Referring to the exploded view of fixator assembly 200, shown in
FIG. 8 and the sectional view shown in FIG. 9, fixator assembly 200
includes a first shaft 202 having a first coupling end 204 and a
first free end 206. First coupling end 204 has an outer diameter
D1. First free end 206 has a narrower diameter than outer diameter
D1. First coupling end 204 terminates in a first lip 207, having a
generally flat face 208 and a generally convex outer face 209. A
first longitudinal axis 210 extends along the length of first shaft
202.
Similarly, a second shaft 212 has a second coupling end 214 and a
second free end 216. Second coupling end 214 has an outer diameter
D2. Second free end 216 has a narrower diameter than outer diameter
D2. Second coupling end 214 terminates in a second lip 217, having
a generally flat face 218 and a generally convex outer face 219. A
second longitudinal axis 220 extends along the length of second
shaft 212.
A coupling 230 pivotally retains first coupling end 204 and second
coupling end 214 therein. Coupling 230 includes a first cup, or
clamshell portion 232 having a concave interface 234 that is
contoured to receive generally convex outer face 209 of first
coupling end 204. Additionally, first clamshell portion 232
includes an opening 236, having a diameter D3, such that outer
diameter D1 of first coupling end 204 is smaller than the diameter
D3, but first lip 207 is larger than the size of opening 236 such
that, when first shaft 202 is inserted through opening 236, first
lip 207 is retained within first clamshell portion 232.
Likewise, coupling 230 also includes a second cup, or clamshell
portion 242 having a concave interface 244 that is contoured to
receive generally convex outer face 219 of second coupling end 214.
Additionally, second clamshell portion 242 includes an opening 246,
having a diameter D4, such that outer diameter D2 of second
coupling end 214 is smaller than the diameter D4, but second lip
217 is larger than the size of opening 246 such that, when second
shaft 212 is inserted through opening 246, second lip 217 is
retained within second clamshell portion 242.
In an exemplary embodiment, first clamshell portion 232 includes
female threads 238 and second clamshell portion 242 includes
matching male threads 248 such that first clamshell portion 232 can
be threadedly connected to second clamshell portion 242.
Optionally, to prevent first clamshell portion 232 from being
separated from second clamshell portion 242, first clamshell
portion 232 can be welded or otherwise permanently secured to
second clamshell portion 242 at the connection of female threads
238 and male threads 248.
As used herein, the term "inner" is used to define a direction
toward coupling 230, and the term "outer" is used to define a
direction away from coupling 230. A first clamp assembly 250 is
disposed on first shaft 202 between coupling 230 and first free end
206 of first shaft 202. First clamp assembly 250 includes a first
inner clamp member 252 disposed proximate to coupling 230. First
inner clamp member 252 has a first inner slot 260. First inner slot
260 has an open end 262, located at a shaft end 263, and a blind
end 264, located at a finger end 265. Finger end 265 includes an
arcuate cutout 266 that extends in an arc greater than 90.degree..
A drill passage 268 extends obliquely through finger end 265 to
allow for the formation of blind end 264.
First inner clamp member 252 also includes a concave surface 269
that engages concave interface 234 of first clamshell portion 232
so that first inner clamp member 252 is slidable along at least a
portion of concave interface 234. Additionally, first inner clamp
member 252 includes a through-opening 270 sized to allow first
shaft 202 to pass therethrough. Through-opening 270 is sized such
that a minimum clearance exists between through-opening 270 and
first shaft 202.
First clamp assembly 250 further includes a first outer clamp
member 272 disposed proximate to first free end 206. First outer
clamp member 272 has a first outer slot 280. First outer slot 280
has an open end 282, located at shaft end 283, and a blind end 284,
located at a finger end 285. Finger end 285 includes an arcuate
cutout 286 that extends in an arc greater than 90.degree.. A drill
passage 288 extends obliquely through finger end 285 to allow for
the formation of blind end 284. Similar to concave surface 269 in
first inner clamp member 252, first outer clamp member 272 also
includes a concave surface 289. Additionally, first outer clamp
member 272 includes a through-opening 290 sized to allow free end
206 of first shaft 202 to pass therethrough.
In an exemplary embodiment, first outer clamp member 272 is
generally a mirror image of first inner clamp member 252 across a
transverse axis 291. When first inner clamp member 252 and first
outer clamp member 272 are assembled on shaft 202, as shown in FIG.
9, a retaining cavity 292 is formed between finger end 265 and
finger end 285. Retaining cavity 292 has a wall portion that
extends an arc of greater than 180.degree.. In an exemplary
embodiment, retaining cavity 292 is sized to allow the insertion of
rod 50 therein.
A first biasing member 294 is disposed in first inner slot 260 and
first outer slot 280. In an exemplary embodiment, first biasing
member 294 is a C-shaped spring having a first end 296 that is
inserted into blind end 264 of first inner slot 260 and a second
end 297 that is inserted into blind end 284 of first outer slot 280
such that first biasing member 294 biases first inner clamp member
252 toward first outer clamp member 272.
A first washer 295 is disposed over first shaft 202 and against
first outer clamp member 272. First washer 295 has a contoured
inner surface 297 for engagement with concave surface 289. A nut
298 is threaded onto first shaft 202 to secure first clamp assembly
250 against coupling 230.
Similar to first clamp assembly 250, a second clamp assembly 350 is
disposed on second shaft 212 between coupling 230 and second free
end 216. Second clamp assembly 350 includes a second inner clamp
member 352 disposed proximate to coupling 230. Second inner clamp
member 352 has a second inner slot 360. Second inner slot 360 has
an open end 362, located at a shaft end 363 and a blind end 364,
located at a finger end 365. Finger end 365 includes an arcuate
cutout 366 that extends in an arc greater than 90.degree.. A drill
passage 368 extends obliquely through finger end 365 to allow for
the formation of blind end 364.
Second inner clamp member 352 also includes a concave surface 369
that engages concave interface 334 of second clamshell portion 242
so that second inner clamp member 352 is slidable along at least a
portion of concave interface 334. Additionally, second inner clamp
member 352 includes a through-opening 370 sized to allow second
shaft 212 to pass therethrough. Through-opening 370 is sized such
that a minimum clearance exists between through-opening 370 and
second shaft 212.
Second clamp assembly 350 further includes a second outer clamp
member 372 disposed proximate to second free end 216. Second outer
clamp member 372 has a second outer slot 380. Second outer slot 380
has an open end 382, located at shaft end 383 and a blind end 384,
located at a finger end 385. Finger end 385 includes an arcuate
cutout 386 that extends in an arc greater than 90.degree.. A drill
passage 388 extends obliquely through finger end 385 to allow for
the formation of blind end 384. Similar to concave surface 369 in
second inner clamp member 352, second outer clamp member 372 also
includes a concave surface 389. Additionally, second outer clamp
member 372 includes a through-opening 390 sized to allow free end
216 of second shaft 212 to pass therethrough.
In an exemplary embodiment, second outer clamp member 372 is
generally a mirror image of second inner clamp member 352 across a
transverse axis 391. When second inner clamp member 352 and second
outer clamp member 372 are assembled on shaft 212, as shown in FIG.
9, a retaining cavity 392 is formed between finger end 365 and
finger end 385. Retaining cavity 392 has a wall portion that
extends an arc of greater than 180.degree.. In an exemplary
embodiment, retaining cavity 392 is sized to allow the insertion of
pin 60 therein.
A second biasing member 394 is disposed in second inner slot 360
and second outer slot 380. In an exemplary embodiment, second
biasing member 394 is a C-shaped spring having a first end 396 that
is inserted into blind end 364 of second inner slot 360 and a
second end 397 that is inserted into blind end 384 of second outer
slot 380 such that second biasing member 394 biases second inner
clamp member 352 toward second outer clamp member 372.
A second washer 395 is disposed over second shaft 212 and against
second outer clamp member 372. Second washer 395 has a contoured
inner surface 397 for engagement with concave surface 389. A nut
398 is threaded onto second shaft 212 to secure second clamp
assembly 350 against coupling 230.
To assemble fixator assembly 200, first shaft 202 is inserted into
first clamshell portion 232, such that first lip 207 is seated in
first clamshell portion 232 and second shaft 212 and second shaft
212 is inserted into second clamshell portion 242, such that second
lip 217 is seated in second clamshell portion 242. First and second
clamshell portion 232, 242 are then fixedly secured to each
other.
First inner clamp member 252 and first outer clamp 272 are placed
next to each other, such that first inner slot 260 and first outer
slot 280 are aligned with each other, forming first clamp assembly
250. First biasing member 294 is then inserted through first inner
slot 260 and first outer slot 280 such that first end 296 of first
biasing member 294 is inserted into blind end 264 of first inner
slot 260 and second end 297 of biasing member 294 is inserted into
blind end 284 of first outer slot 280, thereby securing first inner
clamp member 252 and first outer clamp member 272 to each other and
providing a compressive force to bias finger end 265 of first inner
clamp member 252 and finger end 285 of first outer clamp member 272
toward each other.
First clamp assembly 250 is then slid over first shaft 202 such
that first shaft 202 extends through through-openings 270, 290 and
first shaft 202 extends through first inner slot 260 and first
outer slot 280 such that first shaft 202 retains first biasing
member 294 in first inner slot 260 and first outer slot 280. Washer
295 is slid over first shaft 202 and nut 298 is then threaded onto
first shaft 202 to secure first clamp assembly 250 against coupling
230.
Similarly, second inner clamp member 352 and second outer clamp 372
are placed next to each other, such that second inner slot 360 and
second outer slot 380 are aligned with each other, forming second
clamp assembly 350. Second biasing member 394 is then inserted
through second inner slot 360 and second outer slot 380 such that
first end 396 of second biasing member 394 is inserted into blind
end 364 of second inner slot 360 and second end 397 of biasing
member 394 is inserted into blind end 384 of second outer slot 380,
thereby securing second inner clamp member 352 and second outer
clamp member 372 to each other and providing a compressive force to
bias finger end 365 of second inner clamp member 352 and finger end
385 of second outer clamp member 372 toward each other.
Second clamp assembly 350 is then slid over second shaft 212 such
that second shaft 212 extends through through-openings 370, 390 and
second shaft 212 extends through second inner slot 360 and second
outer slot 280 such that second shaft 212 retains second biasing
member 394 in second inner slot 360 and second outer slot 380.
Washer 395 is slid over second shaft 212, and nut 398 is then
threaded onto second shaft 212 to secure second clamp assembly 350
against coupling 230.
Rod 50 can be inserted into retaining cavity 292. Because retaining
cavity 292 has a wall portion that defines an arc of greater than
180.degree., with rod 50 in retaining cavity 292, the compressive
action of biasing member 294 and the tightening of nut 298 securely
retain rod 50 within retaining cavity 292.
Similarly, pin 60 can be inserted into retaining cavity 392.
Because retaining cavity 392 has a wall portion that defines an arc
of greater than 180.degree., with pin 60 in retaining cavity 392,
the compressive action of biasing member 394 and the tightening of
nut 298 securely retain pin 60 within retaining cavity 392.
In order to rotate first clamp assembly 250 about first shaft 210,
nut 298 can be loosened sufficiently to allow such rotation. The
compressive action of first biasing member 294 retains rod 50
within retaining cavity 292 to allow such rotation, without
adversely affecting the retention of rod 50 within first clamp
assembly 250.
Likewise, in order to rotate second clamp assembly 350 about second
shaft 220, nut 398 can be loosened sufficiently to allow such
rotation. The compressive action of second biasing member 394
retains pin 60 within retaining cavity 392 to allow such rotation,
without adversely affecting the retention of pin 60 within second
clamp assembly 350.
Additionally, because diameter D1 of first coupling end 204 is
smaller than diameter D3 of opening 236 in first clamshell portion
232 and diameter D2 of second coupling end 214 is smaller than
diameter D4 of opening 246 in second clamshell portion 242, first
longitudinal axis 210 of first shaft 202 does not necessarily have
to be collinear with second longitudinal axis 220 of second shaft
212. As shown in FIG. 10, first longitudinal axis 210 can extend at
an oblique angle .beta. relative to second longitudinal axis 220,
allowing for first clamp assembly 250 to angularly pivot relative
to second clamp assembly 350, thereby allowing for angular
adjustment of first clamp assembly 250 relative to second clamp
assembly 350. FIG. 7A shows an example of such angular
adjustment.
According to one embodiment, a method of installing the external
fixator system, for example, at the site of one or more broken
bones, may include inserting a first pin 60 into the afflicted bone
on one side of the fracture; inserting a second pin 60 on an
opposite side of the fracture; attaching a first fixator assembly
200 to the first pin 60 and a second fixator assembly 200 to the
second pin 60; articulating the first or second clamp assembly 250,
350 relative to the other of the first or second clamp assembly
250, 350 into a position for receiving the rod 50; connecting the
rod 50 between the first and second fixator assemblies 200 in order
to secure the first and second pins 60 together. If the construct
needs to be extended, for example, to bridge multiple bones or
multiple fractures, a third fixator assembly 200 may be articulated
and positioned to secure and connect the rod 50 to an additional
rod 50.
It will be further understood that various changes in the details,
materials, and arrangements of the parts which have been described
and illustrated in order to explain the nature of this invention
may be made by those skilled in the art without departing from the
scope of the invention as expressed in the following claims.
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